Thin but visible, a layer of irony hung over yesterday's parliamentary tributes to Nelson Mandela as Britain's political class rushed forward to touch the fallen hero's garment, as if to say: "We'd like to be him, on our best day." Bill Clinton once said just that.

Everyone was aware that South Africa's former colonial power had been complicit in apartheid's creation as well as its destruction, a record like that of no other legislature in the world.

A generation ago, Margaret Thatcher had dismissed him as a terrorist leader and a Tory youth organisation had worn "Hang Nelson Mandela" T-shirts. None were visible on potbellied nostalgics yesterday. But how not to turn a wake into a punch-up?

Mandela-esque restraint was the answer. Speaker Bercow, ex-head of the offending youth organisation, had made it easier by admitting he had been on the wrong side. So did David Cameron, who took an apartheid-sponsored freebie south at the not-so-tender age of 23, but paid a handsome tribute. If reflected glory was part of the day's calculation, so was contrition.

The prime minister can rise to big occasions, but did not do so here. Cameron said all the right things about this "towering figure" who reminded us all that "progress is not just handed down as a gift but won through struggle" – not normally an Etonian sentiment. Yet he rattled through it as if he had a helicopter to catch. When he described the brutality of the old regime, someone cried: "You went there."

Cameron ignored Dennis Skinner's bait and paid the first of many tributes to Peter Hain, the only MP present who had faced serious personal danger in the anti-apartheid cause. Ed Miliband was much more in his comfort zone. He spoke more slowly and more sensitively about Mandela's sacrifice ("a son unable to attend his mother's funeral, a father unable to attend his son's"), and got the first laugh: Mandela's practice of introducing himself as "an unemployed pensioner with a criminal record."

"I am not a saint: I am a sinner who keeps on trying," he had also said. You could almost feel MPs wishing they could say things like that in the constituency and not be laughed at over their 11% pay rise.

Even Gordon Brown's rare intervention was touched by Mandela's special grace. Apart from Hain, he was the one who had known the hero best. There were too many "I's" and "my's", but they shared a passion to eradicate child poverty. Brown spoke of Mandela's courage ( he has a morbid interest in it), and of his belief that we are all equal (except Blairites, obviously), so that Mandela had once rung the Queen for a favour: "Hullo, Elizabeth, How's the duke?"

But it was Miliband who put his finger on two crucial points. One was that the anti-apartheid cause was not always a popular cause. The other was that Westminster does not usually adjourn its sessions for foreign leaders, only for its own.

This is true. The Commons adjourned for JFK in November 1963 after a mere 3,585 words of tribute. But the charismatic president was murdered in his prime (46, not 95) and retired amid universal approbation.

Mandela deserves the honour because the great African stood for historic truth without rancour, for justice, toleration and respect for human dignity, Miliband explained. Was he a Gandhi or a Gorbachev, MPs wondered. Peter Hain evoked the Tolpuddle Martyrs, though a better bet is surely Abraham Lincoln, the greatest public official of the 19th century, who also suffered privately behind a kindly facade.

If Sir Malcolm Rifkind dared point out that Mandela had briefly endorsed the "armed struggle", Hain used his VIP status to repudiate the Tories' "craven indulgence" of apartheid. His stricture was gentle and was accepted – as Mandela would have wished.

Not that virtue was all on one side. Among anti-apartheid unsung foot soldiers is the veteran Tory MP Alistair Burt, who said: "My parents were convinced I had become a communist. Now, like many of my colleagues, they are merely uncertain."